From: "Sven Peter" <sven@svenpeter.dev>
To: "Hector Martin" <marcan@marcan.st>,
"Alyssa Rosenzweig" <alyssa@rosenzweig.io>
Cc: "Wim Van Sebroeck" <wim@linux-watchdog.org>,
"Guenter Roeck" <linux@roeck-us.net>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Kettenis" <mark.kettenis@xs4all.nl>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-watchdog@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] watchdog: Add Apple SoC watchdog driver
Date: Thu, 02 Dec 2021 12:05:41 +0100 [thread overview]
Message-ID: <0abd0537-3485-4b6c-9299-158d26224466@www.fastmail.com> (raw)
In-Reply-To: <ca52e4ee-b5f3-b892-1ba5-7c5656e45fdd@marcan.st>
On Thu, Dec 2, 2021, at 06:14, Hector Martin wrote:
> On 14/11/2021 22.18, Alyssa Rosenzweig wrote:
>>>>> + * This HW block has three separate watchdogs. WD0 resets the machine
>>>>> + * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal
>>>>> + * machine reset. WD0 additionally supports a configurable interrupt.
>>>>
>>>> Do we have any idea what the difference between WD1 and WD2 is?
>>>
>>> I've never seen macOS write to WD2 when running in our hypervisor and only
>>> found that one when I was looking at the rest of the MMIO region.
>>> >From what I can tell it works exactly like WD1.
>>
>> Makes sense, thanks.
>>
>
> Are any of these watchdogs active when we boot, and are we leaving them
> like that? I'm pretty sure at least some of the coprocessors have their
> own watchdog (SMC...), which might be one of these. We should make sure
> we don't clobber that.
That's what I thought at first as well but they are all disabled except for
WD1 which we disable in m1n1.
I don't touch WD0 or WD2 in this driver anyway and v2 also checks if WD1 is
running (because it might've been started by u-boot) and makes sure the
watchdog core is aware and keeps pinging it.
Sven
next prev parent reply other threads:[~2021-12-02 11:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-13 9:47 [PATCH 1/2] dt-bindings: watchdog: Add Apple Watchdog Sven Peter
2021-11-13 9:47 ` [PATCH 2/2] watchdog: Add Apple SoC watchdog driver Sven Peter
2021-11-13 11:14 ` Janne Grunau
2021-11-13 11:19 ` Sven Peter
2021-11-13 15:24 ` Alyssa Rosenzweig
2021-11-14 11:37 ` Sven Peter
2021-11-14 13:18 ` Alyssa Rosenzweig
2021-12-02 5:14 ` Hector Martin
2021-12-02 11:05 ` Sven Peter [this message]
2021-11-14 12:42 ` Guenter Roeck
2021-11-14 13:25 ` Sven Peter
2021-11-13 21:07 ` [PATCH 1/2] dt-bindings: watchdog: Add Apple Watchdog Mark Kettenis
2021-11-14 11:40 ` Sven Peter
2021-11-14 11:58 ` Mark Kettenis
2021-11-29 21:23 ` Rob Herring
2021-11-29 21:24 ` Rob Herring
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